html{
    font-size: 62.5%;  /* 16px*0.625=10px */
}

.value_px{
    font-size: 32px;
}

.value_em{
    font-size: 1em;
}

.value_rem{
    font-size: 2rem;
}

/* 颜色值 */
.color_name{
    color: red;
}

.color_hex{
    color: #00ff00;
}

.color_fun{
    color:rgb(0,0,255)
}

.img_url{
    width: 1000px;
    height: 1000px;
    background-image: url("image/qq_logo.png");
    font-weight: bolder;
}

/* 常见字体样式属性 */
.font_demo{
    /* font: 400; */
    color: red;
    font-family: 微软雅黑,sans-serif;
    font-size: 2em;
    font-style: oblique;
    font-weight: normal;
}

/* 常见文本样式属性 */
.text_demo{
    font-size: 3em;
    border: 1px solid black;
    width: 50rem;
    height: 10rem;
    text-align: left;
    line-height: 10rem;
    text-decoration: underline;
    text-indent: 3rem;
    letter-spacing: 1rem;
    word-spacing: 2rem;
}

/* 列表样式属性 */
ul{
    font-size: 2rem;
}
.list_demo1{
    list-style: circle inside;
}

.list_demo2{
    list-style: none;
}

.list_demo3{
    list-style-image: url(image/qq_logo.png);
    list-style-type: none;
    list-style-position: inside;
}

.list_demo4{
    list-style: none url(image/la.png) inside;
}
